Software controlled stiffening of flexible aircraft

• US 10,279,891 B2
• Filed: 06/02/2016
• Issued: 05/07/2019
• Est. Priority Date: 06/02/2016
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google LLC (Alphabet Inc.)
• Inventors: Krebs, Mark, Brandmeyer, Jonathan Daniel
• Primary Examiner(s): Bonzell, Philip J
• Application Number:
  US15/171,279
• Publication Number:
  US 20170349266A1
• Time in Patent Office: 1,069 Days
• CPC Class Codes: B64C 13/16 actuated automatically, e.g. responsive to gust detectors
• CPC Class Codes: B64C 13/18 using automatic pilot
• CPC Class Codes: B64C 3/38 Adjustment of complete wings or parts thereof
• CPC Class Codes: B64C 3/52 Warping
• CPC Class Codes: B64C 39/10 All-wing aircraft
• CPC Class Codes: B64C 9/04 with compound dependent movements
• CPC Class Codes: B64U 10/25 Fixed-wing aircraft VTOL aircraft B64U10/20
• CPC Class Codes: B64U 30/10 Wings
• CPC Class Codes: G05D 1/0841 to prevent a coupling between different modes

Abstract

Systems and methods for operating control surfaces of an aircraft. The method involves receiving, by an aircraft control system from one or more sensors, deflection information related to a shape and motion of an aircraft, and decomposing, by the aircraft control system, the deflection information into a detected modal state including a first known mode having a first mode strength. The method may further involve determining, by the aircraft control system, a first modal compensation based on the first mode strength, and identifying, by the aircraft control system, a desired control corresponding to a second known mode. The method may yet further involve determining a first control response for a control surface having a first modal weight and a second modal weight, based on the first modal compensation and the first modal weight, and determining a second control response for the control surface based on the desired control and the second modal weight. The method may still further involve generating a control command for the control surface based on the first control response and the second control response.

Claims

1. A method for operating control surfaces of an aircraft having a flexible wing design, the method comprising:

receiving, by an aircraft control system from one or more sensors, deflection information related to a shape and motion of an aircraft having a flexible wing design;

decomposing, by the aircraft control system, the deflection information into a detected modal state comprising a first known mode having a first mode strength;

determining, by the aircraft control system, a first modal compensation based on the first mode strength;

identifying, by the aircraft control system, a desired control corresponding to a second known mode;

determining a first control response for a control surface wherein the control surface has a first modal weight for the first known mode and a second modal weight for the second known mode, and the first control response for the control surface is determined based on the first modal compensation and the first modal weight;

determining a second control response for the control surface based on the desired control and the second modal weight; and

generating a control command for the control surface based on the first control response and the second control response.

2. The method of claim 1, further comprising:

transmitting, by the aircraft control system to a servomotor, the first modal compensation and the desired control,

wherein the determining a first control response, the determining a second control response, and generating a control command for the control surface are performed by the servomotor.

3. The method of claim 1, wherein the first control response corresponds to a first degree of tilt of the control surface and the second control response corresponds to a second degree of tilt of the control surface.

4. The method of claim 1, wherein the detected modal state comprises the second known mode having a second mode strength, and the desired control is a second modal compensation based on the second mode strength.

5. The method of claim 1, further comprising:

determining a first control response for a second control surface wherein the second control surface has a third modal weight for the first mode and a fourth modal weight for the second mode, and the first control response for the second control surface is determined based on the first modal compensation and the third modal weight of the second control surface;

determining a second control response for the second control surface based on the desired control and the fourth modal weight of the second control surface;

generating a control command for the second control surface based on the first control response for the second control surface and the second control response for the second control surface.

6. The method of claim 1, wherein the deflection information comprises strain measurements.

7. The method of claim 1, wherein decomposing the deflection information into a detected modal state comprises convolving the deflection information with the first known mode.

8. The method of claim 1, wherein decomposing the deflection information into a detected modal state comprises convolving the deflection information with each of a plurality of known modes, each convolution with a known mode generating a strength for the known mode.

9. The method of claim 1, wherein the first known mode is a dynamic mode and the second known mode is a structural mode.

10. The method of claim 9, wherein identifying a desired control comprises determining, by an autopilot of the aircraft control system, a desired control.

11. A system for operating control surfaces of an aircraft having a flexible wing design, the system comprising:

one or more sensors configured to detect deflection information related to a shape and motion of the aircraft having a flexible wing design;

an aircraft control system configured to;

receive the deflection information from the one or more sensors;

decompose the deflection information into a detected modal state comprising a first known mode having a first mode strength;

determine a first modal compensation based on the first mode strength; and

identify a desired control corresponding to a second known mode;

a servomotor for a control surface configured to;

determine a first control response wherein the control surface has a first modal weight for the first known mode and a second modal weight for the second known mode, and the first control response for the control surface is determined based on the first modal compensation and the first modal weight;

determine a second control response based on the desired control and the second modal weight;

generate a control command based on the first control response and the second control response; and

one or more control surfaces configured to deflect in accordance with the control command.

12. The system of claim 11, wherein the detected modal state comprises the second known mode having the second mode strength, and the desired control is a second modal compensation based on the second mode strength.

13. The system of claim 11, further comprising a second servomotor configured to:

determine a first control response for a second control surface wherein the second control surface has a third modal weight and a fourth modal weight for the second mode, and the first control response for the second control surface is determined based on the first modal compensation and the third modal weight of the second control surface;

determine a second control response for the second control surface based on the desired control and the fourth modal weight of the second control surface; and

generate a control command for the second control surface based on the first control response for the second control surface and the second control response for the second control surface.

14. The system of claim 11, wherein the deflection information comprises strain measurements.

15. The system of claim 11, wherein the aircraft system is further configured to convolve the deflection information with the first known mode to decompose the deflection information into the detected modal state.

16. The system of claim 11, wherein the aircraft system is further configured to convolve the deflection information with each of a plurality of known modes, each convolution with a known mode generating a strength for the known mode to decompose the deflection information into the detected modal state.

17. The system of claim 11, wherein the servomotor is further configured to aggregate the first control response and the second control response to generate the control command.

18. The system of claim 17, wherein the first control response corresponds to a first degree of tilt of the control surface and the second control response corresponds to a second degree of tilt of the control surface.

19. The system of claim 11, wherein the first known mode is a dynamic mode and the second known mode is a structural mode.

20. The system of claim 19, wherein the aircraft control system comprises an autopilot configured to identify the desired control.